How you showcase your portfolio is very important for any freelancer or design company. It reflects the way you do business, your attention to details and gives an overall feel of professional work. It can mean the difference from getting or losing clients.
To enrich your portfolio showcase you can use Javascripts based on the Prototype or Moo.Fx libraries, scripts such as Litebox, LightBox 2, Highslide JS, ThickBox & many others. These all work just fine, but are a bit too common these days. If you want something special, you have to go the extra distance, XML Flash based gallery scripts.
Here are some resources you can try. They all use XML and ActionScript and are fully customizable.
3D XML Flash Thumbnail Box
3D XML Flash Curve Wall
Spiral Carousel XML Flash script
3D XML Flash Cylinder Box